Ruff M D, Fuller H L
J Nutr. 1975 Nov;105(11):1447-56. doi: 10.1093/jn/105.11.1447.
The levels of plasma carotenoids were markedly reduced in broiler cockerels infected with Eimeria acervulina or E. tenella. The mechanisms of this depigmentation differed between the two species, being primarily associated with interference of absorption of xanthophyll (carotenoids) from the intestinal lumen with E. acervulina infection and with leakage through the damaged wall of the cecum with E. tenella infection. Chicks reared on an essentially carotenoid-free diet and inoculated with E. acervulina showed no detectable levels of carotenoids in the blood 48 hours after being changed to a diet containing 30 mg of xanthophyll/kg. Conversely, uninoculated chicks and chicks inoculated with E. tenella showed significant and similar increases in plasma levels of carotenoids. Chicks reared on a diet containing xanthophyll and inoculated with E. tenella showed a more rapid decrease in plasma carotenoids than did uninoculated controls when changed to a xanthophyll-free diet. In chicks fed high xanthophyll diets containing chromic oxide, no indication of malabsorption was seen in chicks infected with E. tenella compared with uninoculated controls, whereas chicks inoculated with E. acervulina showed significantly less xanthophyll absorption. Conversely, a marked increase in the xanthophyll : Cr2O3 ratio was observed in the cecal contents of chicks inoculated with E. tenella compared with uninuoculated controls or those inoculated with E. acervulina. Studies of uninoculated chicks pair-fed with chicks inoculated with E. acervulina or E. tenella indicated that the decrease in plasma carotenoids and increases in intestinal pH are not associated with the reduced intake of feed associated with infection. The studies involving uninoculated birds with reciprocal chagnes between high and low xanthophyll diets indicated that plasma carotenoids are a more rapid and sensitive means of measuring changes in pigmentation levels than are visual skin scores carotenoid levels from the skin.
感染堆型艾美耳球虫或柔嫩艾美耳球虫的肉用公鸡血浆类胡萝卜素水平显著降低。这两种球虫导致色素沉着减少的机制不同，堆型艾美耳球虫感染主要与肠道腔内叶黄素（类胡萝卜素）吸收受到干扰有关，而柔嫩艾美耳球虫感染则与通过受损盲肠壁的渗漏有关。用基本不含类胡萝卜素的日粮饲养并接种堆型艾美耳球虫的雏鸡，在改为含30毫克叶黄素/千克的日粮48小时后，血液中未检测到类胡萝卜素水平。相反，未接种的雏鸡和接种柔嫩艾美耳球虫的雏鸡血浆类胡萝卜素水平显著且相似地升高。用含叶黄素的日粮饲养并接种柔嫩艾美耳球虫的雏鸡，改为无叶黄素日粮时，血浆类胡萝卜素水平的下降比未接种的对照雏鸡更快。在饲喂含氧化铬的高叶黄素日粮的雏鸡中，与未接种的对照雏鸡相比，感染柔嫩艾美耳球虫的雏鸡未出现吸收不良的迹象，而接种堆型艾美耳球虫的雏鸡叶黄素吸收显著减少。相反，与未接种的对照雏鸡或接种堆型艾美耳球虫的雏鸡相比，接种柔嫩艾美耳球虫的雏鸡盲肠内容物中叶黄素:Cr2O3比值显著升高。对与接种堆型艾美耳球虫或柔嫩艾美耳球虫的雏鸡配对饲养的未接种雏鸡的研究表明，血浆类胡萝卜素的减少和肠道pH值的升高与感染相关的采食量减少无关。涉及在高叶黄素日粮和低叶黄素日粮之间进行相互转换的未接种禽类的研究表明，与视觉皮肤评分相比，血浆类胡萝卜素是一种更快速、更敏感的测量色素沉着水平变化的方法。
